This application claims the priority of Korean Patent Application No. 2002-39729 filed on Jul. 9, 2002 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a receiver-drier used in a cooling system of an air-conditioning system for a car and a method of manufacturing the same, and more particularly, to a body of the receiver-drier and a method of manufacturing the body.
2. Description of the Related Art
A typical cooling system includes a compressor compressing refrigerant, a condenser condensing the refrigerant compressed by the compressor, an expansion valve rapidly expanding the refrigerant which is liquidized by being condensed by the condenser, and an evaporator evaporating the refrigerant expanded in the expansion valve and cooling air blown into the inside of a car utilizing latent heat of vaporization of the refrigerant.
In the process of cooling, first, the compressor driven by the power of an engine compresses refrigerant at a low temperature and low pressure and supplies the compressed refrigerant to the condenser. The condenser condenses the refrigerant whose phase is changed to a state of a high temperature and a high pressure by the compressor by the blowing operation of a cooling fan to make liquid at a high temperature and a high pressure. The refrigerant in the state of a high temperature and a high pressure by being condensed by the condenser is supplied to the evaporator through the expansion valve. The refrigerant is evaporated in the evaporator, absorbs latent heat of vaporization, and is supplied to the compressor. A blow fan sucks air in and out of a car to blow to the inside of the car through the evaporator so that the cooled air is supplied to the inside of the car and the inside of the car is cooled.
In the above cooling process, the refrigerant continuously phase-changes from gas to liquid and from liquid to gas. If foreign materials such as moisture, for example, is included in the refrigerant, the phase is not smoothly changed during the cooling process so that a cooling system cannot work properly or the cooling system may be corroded. In particular, when moisture is mixed in the refrigerant in a cooling system using a refrigerant such as R-12, since the moisture produces hydrochloric acid hydroxide having a strong corrosion feature with respect to metal in a chemical reaction between moisture and the refrigerant, the cooling system is fatally affected.
To solve the moisture problem, typically, a receiver-drier absorbing moisture mixed in the refrigerant is installed between the compressor and the evaporator in the cooling system.
The receiver-drier has a cylindrical body made of metal such as aluminum or iron and a desiccant and a filter are included in the body. Thus, the moisture in the refrigerant flowing from the compressor to the evaporator is absorbed by the desiccant and foreign materials other than the moisture in the refrigerant is filtered by the filter. In addition, the receiver-drier temporarily stores the refrigerant in response to a change in load of a cooling cycle or separates bobbles included in a liquid refrigerant. Also, when a fusible plug is installed and refrigerant is overheated due to malfunction of the cooling system, the refrigerant is forcibly exhausted by using the fusible plug to protect the cooling system.
3. Description of the Related Art
Korean Patent Publication No. 2000-0047336, as shown in FIG. 1, discloses a receiver-drier 100 including a bush 160 which is additionally manufactured and interposed between a lower cap 130 and the body 110, sealing a gap therebetween. In the receiver-drier 100, since the bush 160 needs to be additionally manufactured and assembled, manufacturing cost and time increases.
In the above publication and Korean Patent Publication No. 2001-0000764, as shown in FIGS. 2 and 3, receiver-drier bodies 210 and 310 are disclosed which are manufactured to have a section capable of coupling a lower cap and a receiver-drier body, forming a seal, by using hammers 200 and 300 operating in a lengthwise direction of the receiver-drier body. In this case, the lengths of the receiver-drier bodies 210 and 310 which can be manufactured in a forging process are limited by apparatuses and power for driving the hammers 200 and 300, or excessive residual stress remains in a material of the receiver-drier bodies manufactured in the above method so that durability is deteriorated.